THE EFFECT OF BASIC SOLUTIONS ON THE YELLOWING OF NEWSPAPER. Steven Wendeborn. When solutions with hydroxide ions are sprayed onto newspaper containing oxidizing lignin, the amount of yellowing that is visible after exposure to ultraviolet light varies. The lignin decomposes and acidifies the paper, and when exposed to ultraviolet light and heat transforms through various acids, such as vanillic and succinic, before becoming stable. Aqueous potassium hydroxide, sodium hydroxide, and hydrochloric acid solutions with varying molarities were created and subsequently applied to the newspaper, and then treated newspaper samples were exposed to a weak ultraviolet light source for nine days. A newspaper sample treated with a professional archival spray was also included in the results. The results were quantified using a color chart to determine the shade of yellow, and then compared amongst the samples. The higher the molarity of the samples, and the higher the pH, the less yellow the samples were, and the acid exacerbated the yellowing of the sample. The potassium hydroxide prevented yellowing more than the sodium hydroxide, and the archival spray best preserved the sample. All of the samples treated with a basic solution were less yellow than the control. Keywords: Lignin, acid-base, decomposition, potassium hydroxide, sodium hydroxide, newspaper, ultraviolet light.
Keywords: Lignin, acid-base, decomposition, potassium hydroxide, sodium hydroxide, newspaper, ultraviolet light.